specific_decl_iterator - Construct a new iterator over a subset of the declarations the range [C, end-of-declarations).

If A is non-NULL, it is a pointer to a member function of SpecificDecl that should return true for all of the SpecificDecl instances that will be in the subset of iterators. For example, if you want Objective-C instance methods, SpecificDecl will be ObjCMethodDecl and A will be &ObjCMethodDecl::isInstanceMethod.